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Evolution:
Change over time; the process by which modern
organisms have descended from ancient organisms
∆ 𝒄𝒉𝒂𝒏𝒈𝒆
=
𝒕𝒊𝒎𝒆
𝒕
Tiktaalik:
Transitional fossil
DNA:
Take a minute and write down everything you
know about DNA
End
Chromosomes:
Take a minute and write down everything you
know about Chromosomes
End
Inheritance:
Take a minute and write down everything you
know about how traits are inherited
End
Genes & Alleles
Take a minute and write down everything you
know about genes and alleles
End
Phenotype and Genotype
Take a minute and write down everything you
know about phenotype and genotype
End
Phylogeny
And the evolution of plants
Phylogeny
• Evolutionary history of a species
What is a plant?
All Land Plants
(Embryophytes):
• Alternation of Generations
• Roots & Shoots
• Cuticle (prevents water loss)
Bryophytes: Mosses,
Liverworts and Hornwarts
• What makes them special?
– No vascular tissue
• Can’t transport nutrients -> limited size
– Need water to reproduce
– No seeds
Nonvascular
Plants
Time
Mosses,
liverworts,
hornworts
(vascular tissue)
Ancestral
Algae
(Autotroph)
Vascular Plants
Ferns: Seedless Vascular Plants
• What makes them special?
• No seeds
• Need water to reproduce
Time
Mosses,
liverworts,
hornworts
Seeded Vascular
Plants
Ferns
(Seeds)
(vascular tissue)
Ancestral
Algae
(Autotroph)
Gymnosperm (conifers,
gingkoes, cycads)
• What makes them special?
• Wind pollination, Seeds,
• No flowers
Mosses,
liverworts,
hornworts
Ferns Gymnosperm
Angiosperm
Time
Flowers,
(Seeds)
(vascular tissue)
Ancestral
Algae
(Autotroph)
Angiosperm
(Flowering Plants)
• What makes them special?
• Flowers- pollination by animals
• Double fertilization
– Seed doesn't develop w/out pollination
Modeling Phylogenetic Trees
Ferns
Gymnosperm
Time
Mosses,
liverworts,
hornworts
Angiosperm
Look at the Nodes
Ancestral
Algae
Any of the branches can be rotated
at the nodes:
Mosses,
Ferns
Angiosperm
Time
liverworts,
hornworts
Gymnosperm
Look at the Nodes
Ancestral
Algae
Are Angiosperm more closely related to Ferns, or to
mosses/liverworts and hornworts?
Gymnosperm
Time
Ferns
Ferns
Angiosperm
Mosses,
liverworts,
hornworts
Are Ferns more closely related to Angiosperm, or to
Gymosperm?
Angiosperm
Ferns
Time
Gymnosperm
Mosses,
liverworts,
hornworts
Neither: They are equally related
Tree of Life
Tree of Life
Bonus Opportunity
• Fantasy Phylogeny
– Create a phylogenetic tree of fantasy
creatures
– Include at least 5 creatures
– Include descriptions of creatures
– Describe characteristic that is
associated with each node
(example: seeds, vascular tissue in plants)
Lizard Lab
• 3 Parts- must be done sequentially.
When you complete part 1, return
that handout and pickup the next.
• Turn in at end of class- we will be working
on them next class also. They are due on _____
Evolution: A more
technical definition
frequency in
• the change in allele __________
a population, over _________.
time
Mechanisms of Evolution
• Mutation
Change in the DNA code
“Instant Evolution”
Almost always harmful. Why?
Mechanisms of Evolution
• Migration
Movement of organisms in or out of a population
Changes allele frequency
Mechanisms of Evolution
Drift
• Genetic
_________which
is a sampling
______ error.
Founder Effect
– ____________in
which a population is
isolated from the parent population.
• This new population is a random sample of
the original, containing different
Allele
frequencies
______________
Mechanisms of Evolution
Drift
• Genetic
_________which
is a sampling
______ error.
Bottleneck Effect
– ___________
in which a population
declines rapidly, so that only a small
number of members remains. The
remaining members are essentially
frequencies
a random
sample and have different Allele
______,
_________
than the parent population.
Cheetahs underwent this. The population
– ______
99
shares ____%
of their DNA- they are
siblings
more closely related than most _____.
Mechanisms of Evolution
• ______
Natural _______
Selection was proposed by
______
_____ in The Origin of Species.
Charles Darwin
Conditions:
– There must be variation
_______
heritable
variation
– The ________must
be ________
survive
– More are born
____ than will _________.
variations survive better than
– Some ________
others.
Mechanisms of Evolution
• ______
Natural _______
Selection increases
fitness
__________,
which is measured in the
number of offspring an individual has,
relative to other members of its
species..
Definitions: Genotype vs
Phenotype
• Genotype:
What your genes are; 2 alleles
• Phenotype:
What you look like; your appearance
Genotype or Phenotype?
• The bunny has brown fur…
Phenotype
Genotype or Phenotype?
• Lucy is a carrier for X-linked color
blindness.
Genotype
Genotype or Phenotype?
• The flowers are pink.
Phenotype
Genotype or Phenotype?
• The plants are short
Phenotype
Definitions: Dominant &
Recessive
• Dominant:
Represented by a capital letter
Single copy determines the trait
“overrides” other alleles
• Recessive:
Represented by a lower-case letter
Can be “masked”
Dominant or Recessive
• The “O” in blood types Recessive
– It may be helpful to know that an
individual with an AO genotype has
type A, and an individual with BO has
type B, while an individual with OO
has blood type O
Dominant or Recessive
Dominant
• If an individual inherits even a
single copy of the allele associated
with Huntington’s disease, the
individual will develop the disease.
Dominant or Recessive
Recessive
• Brown-eyed parents sometimes
have blue-eyed children. Is the
blue eyed allele dominant, or
recessive?
Definitions: Homozygous
& Heterozygous
• Homozygous:
Homo- prefix meaning same
Refers to an organism with 2 identical copies
of an allele. Example: AA or aa
• Heterozygous
Hetero- prefix meaning different
Refers to an organism with 2 different alleles
Example: Aa
A) homozygous dominant…
B) homozygous recessive…
C) heterozygous…?
• AA
Homozygous dominant
A) homozygous dominant…
B) homozygous recessive…
C) heterozygous…?
• Aa
Heterozygous
A) homozygous dominant…
B) homozygous recessive…
C) heterozygous…?
• An individual is a carrier for sickle
cell disease Heterozygous
A) homozygous dominant…
B) homozygous recessive…
C) heterozygous…?
• Pure breeding purple flowers,
given that crossing purple and
white flowers will result in purple
flowers.
Homozygous dominant
A) homozygous dominant…
B) homozygous recessive…
C) heterozygous…?
• An individual with O blood type.
Homozygous recessive
Write the genotype:
• Homozygous dominant
– (use ‘A’ and ‘a’ to represent the alleles)
AA
Write the genotype:
• An individual that will not develop
Huntington's disease.
aa
Write the genotype:
• An individual with blue eyes. Use ’B’ and ‘b’ to
represent the alleles
bb
Write the genotype:
• Mary has type A, blood type, but
her father had type O.
AO
Hardy-Weinberg Principle
allele
• Principle stating that _______
change unless
frequencies do not _____
there is a factor causing change
Hardy-Weinberg Principle
Assumes:
–
–
–
–
–
Large population
No Migration
Random Mating
No Mutations
No Selection
Hardy-Weinberg Principle
• Equations: 𝑝 + 𝑞 = 1
– Where 𝑝 is: frequency of the
dominant allele
– Where 𝑞 is: frequency of the
recessive allele
Hardy-Weinberg Principle
• Equations: 𝑝2 + 2𝑝𝑞 + 𝑞 2 = 1
• Where 𝑝2 is: frequency of homozygous
•
dominant genotype in population
Where 𝑞 2 is: frequency of homozygous
recessive genotype in population
• Where 2𝑝𝑞 is:
frequency of heterozygous
genotype in population
Hardy-Weinberg Principle
• Video on how to solve HardyWeinberg problems
• If the frequency of the dominant
allele is .3
– What is the frequency of the
recessive allele?
Given:
𝑝 = .3
Equation:
𝑝+𝑞 =1
𝑞 =1−𝑝
𝑞 = 1 − .3
𝑞 = .7
• If the frequency of the dominant
allele is .3 𝑝 = .3 𝑞 = .7
– What percentage of the population
will be heterozygous for the trait?
Equation:
𝑝2 + 2𝑝𝑞 + 𝑞2 = 1
Calculate 2pq
2𝑝𝑞 = 2 ∙ .3 ∙ (.7)
2𝑝𝑞 = .42
So, 42%
Solve:
The frequency of the homozygous
recessive genotype is 0.09. What is
the frequency of individuals that are
homozygous for the dominant allele?
Given:
Find:
𝑞 = .09
𝑝2 =
𝑝+𝑞 =1
𝑝=1−𝑞
𝑝 = 1 − .09
𝑝 = .91
(.91)2 =.83
Solve:
The frequency of the homozygous
recessive genotype is 0.09. In a
population of 1000, how many would
have the dominant phenotype ?
Given:
𝑞 = .09
𝑝 = .91
Find:
1000 ∗ (2𝑝𝑞 + 𝑝2 ) =
1000 ∗ (2 (.09)(.91) + (.91)2 ) = 9938
Solve:
If the frequency of two alleles in a
gene pool is 90% A and 10% a,
what is the frequency of individuals
in the population with the
genotype Aa?
Find:
Given:
𝑝 = .9
𝑞 = .1
2𝑝𝑞 =
2 .9 . 1) = .18
Solve:
In humans, Rh-positive individuals have the Rh
antigen on their red blood cells, while Rh-negative
individuals do not. If the Rh-positive phenotype is
produced by a dominant gene (A), and the Rhnegative phenotype is due to its recessive allele
(a), what is the frequency of the Rh-positive allele
if 84% of a population is Rh-positive?
Given:
Find:
2𝑝𝑞 + 𝑝2 = .84
𝑝2 + 2𝑝𝑞 + 𝑞2 = 1
𝑞2 = 1-(𝑝2 + 2𝑝𝑞)
𝑞2 = 1-.84
𝑞2 = .16
𝑞2 = .16
𝑞 = .4
𝑝=
𝑝=
𝑝+𝑞 =1
Linking HW to Genetic
Drift
• Bozeman Bio:
https://youtu.be/mjQ_yN5znyk?t=
63
Problem 1- first set of
Hardy-Weinberg Problems